Triphenylphosphine → 4-[1,1-Dimethyl-3-(2-methoxyphenyl)-2-propynyloxy]benzonitrile

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Reaction Steps

The 4-(2-methoxyphenyl)-2.2-dimethyl-2H-1-benzopyran-6-carbonitrile used as the starting material was prepared as follows: (A) 2.34 g of 2-iodoanisole were added at room temperature to a solution of 9 mg of palladium(II) chloride, 26 mg of o triphenylphosphine and 19 mg of copper(I) iodide in 25 ml of diethylamine. This mixture was treated with 1.85 g of 4-(1,1-dimethyl-2-propynyloxy)benzonitrile and the resulting mixture was stirred for 48 hours. The mixture was evaporated and the residue was dissolved in a mixture of ethyl acetate and water. The organic phase was separated, dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:4) for the elution to give 0.99 g of 4-[1,1-dimethyl-3-(2-methoxyphenyl)-2-propynyloxy]benzonitrile in the form of an oil. (B) 0.99 g of 4-[1,1-dimethyl-3-(2-methoxyphenyl)-2-propynyloxy]benzonitrile was dissolved in 10 ml of 1,2-dichlorobenzene and heated at reflux for 1.5 hours. After cooling the solution was evaporated and the residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:4) for the elution. After recrystallization from petroleum ether (boiling point 60°-80° C.) there were obtained 480 mg of 4-(2-methoxyphenyl)-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile of melting point 109°-111° C.

Provenance & Evidence